1. Field of the Invention
The invention relates generally to a method of determining lunar-based events and, more particularly, to a method of determining an Islamic Hijri religious calendar.
2. Description of the Related Art
Many events, such as the Islamic religious Hijri calendar, are based upon actual lunar observations. The religious Hijri calendar year comprises twelve lunar months, each month comprising of 29 or 30 days, beginning at sunset on the day of a visual sighting of a lunar crescent. If the lunar crescent is visible at sunset of the 29th day, a new month begins, resulting in a month of 29 days. If the lunar crescent is not visible at sunset of the 29th day, however, the current month continues for one additional day, resulting in a month of 30 days. As a result, the religious Hijri calendar may not be accurately calculated in advance.
The visual sighting of the lunar crescent depends on the position of the moon relative to a geographic location and the weather conditions, among others. The position of the moon relative to a geographic location of an observer provides an indication of when the lunar crescent will be visible above the Earth""s horizon. The ability to calculate the position of the moon relative to a geographic location, such as a latitude and longitude, is well known to a person of ordinary skill in the art.
The second factor, however, is dependent upon the visibility of the lunar crescent at a specific location. The visibility of the lunar crescent depends upon the weather conditions, among other things, which may not be accurately forecasted to allow the creation of the religious Hijri calendar in advance.
Prior attempts to determine the religious Hijri calendar are not accurate. One attempt, also referred to as the civil Hijri calendar, comprises calculating the lunar position relative to a given location, such as the latitude and longitude. This method, however, does not consider weather conditions that may affect the actual visibility of the lunar crescent. As a result, this method may falsely indicate the start of a month.
Another attempt to determine the religious Hijri calendar comprises observing and announcing the visibility of the moon on a regional basis, such as by a country. This method, however, does not consider the weather conditions in various parts of the country and, as a result, may again falsely indicate the start of a month for some parts of the region.
Therefore, there is a need for calculating the religious Hijri calendar taking into consideration the visibility of the lunar crescent.
The present invention comprises a method and an apparatus for calculating the beginning of a new lunar month by providing a user with web observation of the sky in the direction of the moon for the purpose of determining whether the moon is visible. Alternatively, a weather report may also be accessed to determine if the weather conditions are suitable for viewing the moon. Upon a determination that the moon is visible, the beginning of the new lunar month is indicated. If, however, a determination is made that the moon is not visible, then the lunar month continues for another day.